Tower foundation guide rod nut

ABSTRACT

A tower foundation ( 10 ) has a base slab ( 11 ), pillar slabs ( 12 ), and a crown stab ( 13 ), all of which are made of precast concrete structures. The slabs are all retained in position by steel guide rods ( 15 ) that extend upwardly from the base slab. The guide rods have externally threaded lower ends ( 16 ) configured, to receive internally threaded guide rod mounting nuts ( 17 ) which have a metal mounting plate ( 20 ) with a guide rod hole ( 21 ) therethrough, a main body portion ( 22 ) welded to the mounting plate and having a threaded channel ( 23 ) therethrough, and a sealing plate ( 24 ) coupled to bottom of the main body portion through a peripheral weld ( 25 ) so as to seal the bottom opening of the threaded channel.

TECHNICAL FIELD

This invention relates to foundation slabs, and particularly to thethreaded guide rod nuts utilized in foundations made of precast concreteslabs.

BACKGROUND OF THE INVENTION

Today there exists a vast number of towers, such as cellular telephonetowers, railroad communication tower utilizing microwave, radio andsatellite communications, and tilt-down towers, being erected across thecountry. Each tower includes a foundation which is typically embeddedwithin the ground to prevent the tower for toppling over.

In the past, these foundations have been constructed by merely digging ahole in the ground and filling the hole with concrete to which theupright towers is anchored. This has been costly in that it requiresthat mixed concrete in fluid form be transported to each site, requiresa curing time to pass before the next step of the process can becomplete, thereby slowing the construction process and increasing costs,and requires a time or inspection delay between construction eventswhich can cause days of delays to occur.

More recently, foundations have been made of a series of precastconcrete components. The precast concrete components include large slabswith holes therethrough through which guide rods extend that coupled theslabs together. The bottommost slab includes a threaded guide rodmounting nut into which each guide rod is threadably mounted. Theseguide rod mounting nuts may include a small bar welded across the bottomof the nut to limit the travel of the bar. However, these guide rodmounting nuts and their corresponding guide rods tend to corrode overtime due to the leaching of elements from the concrete, especially inthe area of the threads of each.

Accordingly, it is seen that a precast tower foundation guide rodmounting nuts that overcomes or alleviates the just described problemsis needed. It is to the provision of such therefore that the presentinvention is primarily directed.

SUMMARY OF THE INVENTION

A tower foundation base slab comprises a concrete body portion having atop surface, a bottom surface opposite the top surface. The base slabalso includes a plurality of guide rod mounting nuts embedded within theconcrete body portion, each guide rod mounting nut having a mountingplate with a guide rod hole therethrough, a main body portion having aninternally threaded channel extending generally vertically between a topopening and a bottom opening, the main body portion being positionedbelow the mounting plate and having the internally threaded channelaligned with the mounting plate guide rod hole, and a sealing platecoupled to the main body portion opposite the mounting plate completelysealing the channel bottom opening. The tower foundation base slab alsohas a plurality of guide rod mounting holes extending between themounting plate guide rod hole and the concrete body portion top surface.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a tower foundation embodying principlesof the invention in a preferred form.

FIG. 2 is a top view of the crown slab of the foundation of FIG. 1.

FIG. 3 is a cross-sectional view of the crown slab of a portion of thefoundation of FIG. 1.

FIG. 4 is a perspective view of the compression washer assembly of thetower foundation of FIG. 1.

FIG. 5 s a cross-sectional view of a portion of the base slab of thefoundation of FIG. 1.

FIG. 6 is a perspective view of a guide rod mounting nut of thefoundation of FIG. 1.

DETAILED DESCRIPTION

With reference next to the drawing, there is shown a tower foundation 10of the present invention in a preferred form. The foundation here has abase or bottom slab 11, a plurality of pillar or middle slabs 12, and acrown or top stab 13, all of which are made of precast concretestructures. The base slab 11, pillar slabs 12 and crown slab 13 are allretained in position by four steel guide rods 15 that extend upwardlyfrom the base slab 11. The four guide rods 15 have externally threadedlower ends 16 configured to be received within internally threaded guiderod mounting nuts 17 which are embedded within the bottom slab 11. Thefour guide rods 15 also have externally threaded upper ends 18configured to be received within internally threaded foundation securingnuts 19. Each guide rod mounting nut 17 has a metal mounting plate 20with a guide rod hole 21 therethrough which is aligned with a base slabguide rod mounting hole 27. The guide rod mounting nut also has athreaded main body portion welded to the mounting plate 20 and having athreaded channel 23 therethrough axially or longitudinally aligned withthe mounting plate guide rod hole 21 and configured to threadably matewith the lower end 16 of the guide rods, and a sealing plate 24 coupledto bottom of the main body portion 22 through a peripheral weld 25 so asto completely seal the bottom opening of the threaded channel 23.

The two pillar slabs 12 are generally X-shaped (four legs 12′) and restupon the base slab 11. The pillar slabs 12 have four guide rod mountingholes 30 extending therethrough positioned to be aligned with the guiderods 15. The pillar slabs 12 are mounted on the four guide rods 15 atopthe base slab 11.

Finally, the crown slab 13 is mounted atop the pillar slabs 12. Theconcrete crown slab 13 has a body portion with four guide rod mountingholes 32 extending therethrough through which the guide rods 15 extend.The crown slab also includes four unshown eye bolts extending from eyebolt mounting holes and embedded inserts within the top surface.

The crown slab 13 also has four compression washer assemblies 35partially embedded therein. Each compression washer assembly 35 includesa metal pressure plate, main. plate, or washer 36 and a pair ofoppositely disposed mounting or anchor legs 37 mounted to the pressurewasher 36. The pressure washer 36 has a central mounting hole 38coaxially aligned with the crown slab guide rod mounting holes 32through which the guide rod extends. The pressure washer 36 has a topsurface 39 which is positioned generally coplanar or flush with the topsurface 40 of the crown slab and therefore exposed from the top. Theanchor legs 37 are embedded within the crown slab to providereinforcement and stability.

With this construction, the slabs 11, 12 and 13 are assembled with theguide rods extending through each slab's axially aligned mounting holes(32, 30 and 27) with the guide rods' lower end 16 extending through theguide rod hole 21 of the mounting plate 20 and threaded into thethreaded channel 23 of the main body portion 22. The guide rods' upperends 18 extending past the top surface 40 of the crown slab 13 so as toreceive the foundation securing nuts 19. The sealing plate 24 of theguide rod mounting nuts 17 also acts as a stop to prevent the guide rodsfrom extending completely through the guide rod mounting nuts should itbe overly threaded into the main body portion 22, which prevents theguide rods from punching through the concrete below the guide rodmounting nuts 17. The positioning of the main body portion 22 below themounting plate 20 causes any upward pulling force upon the guide rodmounting nuts to be dissipated throughout the mounting plate 20 whileforcing the main body portion against the mounting plate to preventseparation therebetween. The larger size and surface area of themounting plate with respect to the main body portion also dissipates theforce over a larger area.

This construction of the foundation allows the weight of the tower to bedissipated through the pressure washer 26 and into the rest of thefoundation, rather than being loaded upon the guide rods and solely tothe base of the foundation. The threaded foundation securing nuts 19 arethen threaded onto the rods upper end 18 to a position wherein they arein direct contact with and bear tightly against the top surface 39 ofthe pressure washer 36. As such, the guide rod foundation securing nuts19 bear against a solid metal plate like structure. Thus, the guide rodtower mounting nuts no longer bears against concrete which issusceptible to chipping or wearing due to vibrations or other types ofmovement. The elimination of the concrete wearing problem enables thetower mounting nuts r be better secured and the tower foundation to bemore rigid and therefore safer in initial construction as well as overan extended period of time.

The threaded upper ends 18 of the guide rods extend past the top surface40 of the crown slab 13. A tower T, or the like, is then coupled to theupper end 18 and secured in place on each rod by a pair of threadedtower mounting nuts 42. The relative positions of the tower mountingnuts 42 along the guide rod 15 may be adjusted to level the tower.

Once the foundation is placed in the ground and the dirt is packedtightly around the foundation the dirt is pressed tightly against thesidewalls of the pillar slabs.

Typically, the foundation of FIG. 1 is used to support cellular towersor the like, but may be used for any type of tower, signage, signal orother device, and thus the term tower and/or tower foundation isutilized herein as a generic term for any pole, vertical structure, ortower-like structure mounted to the foundation. As such, the term towerfoundation is not meant to be a limitation, but merely a description ofone use of structure used in conjunction with the foundation.

It should be understood that any number and peripheral shape of pillarslabs may be utilized with the present invention, the number and size ofslabs depends on the size and weight of the slabs and on the size,height and weight of the tower coupled thereto. Also, it should beunderstood that the base and crown slabs may also be configured tohaving tapered sidewalls.

The foundation slabs may b manufactured in the convention fashion, suchas the method described in U.S. Pat. No. 6,257,489 which is incorporatedherein by reference.

It should be understood that the sealing of the guide rod mounting nut'sbottom opening prevents elements which leach from the concrete fromentering the threaded channel 23 of the guide rod mounting nuts. Thissealing of the threaded channel resists corrosion of the metal guiderods and the threads of the metal guide rod mounting nuts 17 and theirresulting weakening therefrom.

It thus is seen that a tower foundation is now provided that overcomesproblems long associated with those of the prior art. It should beunderstood however that many modifications, additions and deletions maybe made to the embodiments specifically described without departing fromthe spirit and scope of the invention as set forth in the followingclaims.

1. A tower foundation base slab comprising, a concrete body portionhaving a top surface, a bottom surface opposite said top surface; aplurality of guide rod mounting nuts embedded within said concrete bodyportion, each guide rod mounting nut having a mounting plate with aguide rod hole therethrough, a main body portion having an internallythreaded channel extending generally vertically between a channel topopening and a channel bottom, opening, said main body portion beingpositioned below said mounting plate and having said internally threadedchannel aligned with said mounting plate guide rod hole, and a sealingplate coupled to said main body portion opposite said mounting platecompletely sealing said channel bottom opening, and a plurality of guiderod mounting holes extending between said mounting plate guide rod holeand said concrete body portion top surface.
 2. The tower foundation ofclaim 1 wherein said main body portion of said guide rod mounting nut iswelded to said mounting plate of said guide rod mounting nut.
 3. A towerfoundation comprising: a concrete base slab having a plurality of guiderod mounting holes extending from a top surface to a plurality of guiderod mounting nuts, each nut having a mounting plate coupled to a mainbody portion with a threaded channel therethrough and a sealing platesealing a bottom opening of said threaded channel, at least one pillarslab having a plurality of guide rod mounting holes aligned with saidbase slab guide rod mounting holes, a concrete crown slab having aplurality of guide rod mounting holes aligned with said at least onepillar slab plurality of guide rod mounting holes; a plurality of guiderods, each said guide rod extending through one said base slab guide rodmounting hole, one said pillar slab guide rod mounting hole, one saidcrown slab guide rod mounting hole, and threaded into one said threadedchannel of said guide rod mounting nut main body portion.
 4. The towerfoundation of claim 3 wherein said main body portion of said guide rodmounting nut is welded to said mounting plate of said guide rod mountingnut.
 5. A tower foundation base slab comprising, a concrete body portionhaving a top surface, a bottom surface opposite said top surface; aplurality of guide rod mounting nuts embedded within said concrete bodyportion, each guide rod mounting nut having a plate with a guide rodhole therethrough, a main body portion permanently mounted to saidplate, said main body portion including a threaded channel therethrough,and a sealing plate coupled to said main body portion and sealing oneend of said channel, and a plurality of guide rod mounting holesextending from said concrete body portion top surface to said main bodyportion threaded channel.
 6. The tower foundation of claim 5 whereinsaid main body portion of said guide rod mounting nut is welded to saidplate of said guide rod mounting nut.
 7. The tower foundation of claim 5wherein said guide rod mounting nut plate is positioned directly abovesaid guide rod mounting nut main body portion.
 8. The tower foundationof claim 7 wherein said plate guide rod hole is axially aligned withsaid threaded channel.